Catalyst supports are widely used in the various chemical industries. Such supports are normally highly porous pellets composed primarily of silica or mixtures of silica and alumina. The porous nature of the pellets give them considerable surface area. On the surfaces are deposited small amounts of catalytically active materials, such as metals or acids. Use of the support with a catalytically active material greatly increases the efficiency of use of the latter, for by spreading the material over a large support surface area much more of its catalytically active surface is exposed to the chemicals whose reaction it is to catalyze.
The precise nature of the catalyst support will depend on the particular catalytic reaction for which it is to be used. Thus there are many significant differences in the preparation processes with different catalyst supports so that parameters such as pore size and effective surface area can be controlled.